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2.9 Open Compatibility

For backward compatibility, it is permitted in SETL to ignore the result of open (which in the old CIMS SETL returned true or false), and simply refer to open files by the same name as originally passed to open in all subsequent I/O calls, provided this name is unambiguous (which will not be the case when the same file is open more than once simultaneously, or when more than one child process identified by the same command string, such as `wish', is open).

SETL2 programs, which must treat the ``file handle'' returned by the SETL2 open as an opaque entity, should be immediately portable to the SETL described here without change, except that some differences will be observed in the way values are presented by the corresponding versions of procedures like printa.


next up previous
Next: 2.10 Automatically Opened Files Up: 2. Environmentally Friendly I/O Previous: 2.8 Processes and Process Groups
David Bacon
1999-12-10